Chisel retainer for pneumatic hammers



Patented Nov. `9, 194g UNITED sTATEs PATENT OFFICE CHISEL RETAINER FOR PNEUMATIC HAMMERS William H. Peck, Royal Oak, Mich. Application June 26, 1947, Serial No. 757,177

This invention relates to a pneumatic hammer,

and more particularly to a locking device for retaining a chisel on the hammer barrel.

An object of the invention is to provide a chisel retainer which is quickly operated for retaining the chisel in operating position and which will permit easy replacement ofthe chisel when it is desired to substitute one tool for another.

Another object of the invention is to provide a chisel locking device which may be manufactured as a unit assembly and press fitted on to the end of the hammer barrel.

A further object of the invention is to provide an improved gripping surface on the chisel for cooperation with the improved locking device.

Other objects and advantages of -the invention will more fully appear from the following description taken in connection with the accompanying drawings in which: Y

Fig. 1 is a side elevational view of a penumatic hammer showing the improved chiselr locking device applied thereon;

Fig.` 2 is an enlarged sectional view taken on line 2-2 of Fig. 1;

Figs. 3, 4 and 5 are views corresponding to Fig. 2 but showing diierent positions of the locking ring;

Fig. 6 is a sectional View taken on line 6-6 of Fig. 2;

Fig. '7 is a sectional view taken on line 1-1 of Figy; and

Fig. 8 is a sectional view corresponding to Fig. 2 but showing a modified form of the invention.

Referring to the drawings, a pneumatic hammer I6, having a barrel I2 and a handle I4, is shown with the improved chisel locking device applied thereto. The handle has a connection I6 for communication with an air pressure line I8 connected to a source of pressure, not shown. A control is shown at 2D for admitting the air pressure to the operating parts of the hammer which are conventional construction.

A chisel 22 is removably received in the barrel end of the hammer and is securely held in operating position by the locking mechanism more fully illustrated in Figs. 2-8 inclusive.

In pneumatic hammers of the type selected for illustrating the invention, the barrel l2 receives the shank end of the chisel. Heretofore, a bushing in the barrell end formed a guide for the inner end of the chisel shank. In my improved construction, the bushing is replaced by a part 24 having an inner tubular portion 26 adapted to be press fitted in the barrel in place of the bushing. The part 24 has an outer enlarged sleeve portion,

2 Claims. (Cl. 279-195) hereinafter referred to as the ball cage 28, and a radially extending flange 30 is formed onthe outer end of the part 24.

Ball receiving apertures 32 are formed inthe wall of the ball cage 28 for the reception of balls 34 having a diameter greater than the wall thickness of the ball cage 28. TheV apertures are preferably tapered to prevent the balls from passing entirely through the apertures.

A sleeve 36 surrounds the ball cage 28 and is provided with an inwardly extending iiange 38 bearing on the outer periphery of the ball cage 28. The inner end of the sleeve 36 is spaced from the outer periphery of the ball cage 28 to provide a space for a compression spring 40 having one end abutting the inner surface ofthe flange `38 and its opposite end abutting a retaining ring 42 which is press fitted on theouter periphery of the tubular portion 26. The inner periphery of the `sleeve 36 slidablyts the outer periphery` of the retaining ring 42.

In assembly of the devicethe balls 34 are placed in the apertures 32 and the sleeve is slid over the inner end of `the ball cage 28. The compression spring 4l] is then inserted between the sleeve 36 and the ball cage 28. Finally the retaining ring 42 is pressed on the tubular portion 26 subjecting the spring 4D to compression and urging the sleeve 36 against the flange 30. The entire assembly is then secured to the barrel by pressing the tubular portion 26 into the open end of the barrel l2 with the inner end of the retaining ring 42 abutting the outer end of the barrel.

An outwardly projecting member 44, in the form of a pin, is inserted in the outer `end face of the sleeve 36 adapted to be received in an opening 46 in the inner face of the ange 36.

'I'he inner periphery of the iiange 38 is provided with circumferentially spaced recesses 48, corresponding in number t0 the balls 3,4 and which are correspondingly spaced.

The chisel 22 has an annular inner end portion 5B which slidingly ts within the tubular portion 26 and an enlarged flange 52 which slidingly ts within the ball cage 28 of `larger inner diameter than the inner diameter of the tubular portion 26. tapered inwardly toward the tool end in the region adjacent the shank contact with the balls The shank, outwardly of the flange 52, is

rasate@ balls radially inwardly into holding position. This position is determined by the pin 44 in the aperture 46. When it is desired ,to remove the chisel from the barrel, the sleeve 36 is slid axially into the position shown in Fig. 3 to free the pin M from the apertures 46. 'I'he sleeve is then turned to the position shown in Fig. 4 with the recesses i3 opposite the balls ,34. Whenathe chisel is removed, the llange 5.2 =forces the balls partially into the recesses 48, as shown in Fig. 5 so that the chisel is freely withdrawn from the device.

A shoulder 5d is formed on the shank outwardly beyond the balls 34. The distance between `the shoulder 54 and the balls 34 is substantially equal to the distance between the inner ,edge v of the i flange 52 and the shoulder portion formed by the tubular portion 2li. When the'toollis in'loperation' the operator forces the tool inwardly so.that ,the shoulder 5d bears against the balls 34 providing a freely rotatable tool and a bearing stop for the tool.

' In the forni of the invention'shown inFigfS, the parts, are substantially the same as shownin Figs. 2 to '7 inclusive, vexcept that the tubular portion 2li is made of larger diameter so that'it can be press tted over the outer end of the barrel rather than press tted within the barrel. This form may be found expedient when 'it is not desirable to replace the bushing in the standard hammer for the sleeve 26.

It will be understood that various changes including the size, shape and arrangement of parts may be made without departing from the spirit of my invention, and it is not my intention to limit its scope other than by the `terms of the appended claims.

I claim:

1. A krelea-sable holding means for a'shanked tool at the end of the'barrel of apneumatic-hammer Comprising a tubular member constructed and arranged for press t insertion into the open end of the hammer barrel and toslidingly re- -ceive the shank of a tool therein; aball cage having a diameter greater than the diameter of said tubular member having a plurality of circumferentially spaced apertures through the wall thereof, balls in the apertures of said ball cage, an axially slidable and rotatable sleeve having circumferentially spaced recesses in its inner periphery over said ball cage, an outwardly extending flange at the outer end of said ball cage for limiting the outward axial movement of said sleeve, ,and a .retainingring press .,tted on said :tubular member ,for limiting the linward axial movement of said sleeve.

.2. A releasable holding means for a shanked tool at the end of the barrel of a pneumatic hammer :comprising :a tubular member constructed and arranged for press t insertion into the open .rend of .the,hammer barrel and to slidingly receive the shank of a tool therein; a ball cage having/.afdiameter @greater than the diameter of said tubular `member having a plurality of circumferentially spaced apertures through the wall thereof, balls inthe aperturesy of said ball,ca gean axially slidable andfrotatable sleeveha'ving circumferentially spaced recesses Ain'its inner periphery over said bally cage, an outwardly extending flange at the -outer endof saidball cage for limitingthe outward axial-movement of said sleeve,fa1retain ing ring press 'tted yon said tubular member "for limiting the inward axial-movement of said sleeve, and a compression spring operable between said sleeve and said-retaining ring.

fHJPECK.

REFERENCES iCI'IlED vThe 4following references ,are .of record in the le of `this patent: 

